Most automobile alarm manufactures or distributors offer in their product line a device that when installed properly can automatically start up a vehicle""s engine and maintain electrical circuits necessary to operate vehicle mounted electrical accessories. These devices are typically triggered by an input signal derived from a radio frequency receiver that is either a stand alone device, or exist as part of an automobile alarm system. The automatic starting devices are designed to accept a momentary negative 12-15 VDC of approximately 0.5 seconds to the activation input of the auto start device where reception of such a signal would constitute a valid activation command and cause the auto start device to initiate and maintain the run mode. The run mode will typically remain engaged for a pre determined length of time and upon expiration of that time the device will disengaged the run mode and return to a standby status. If a second signal is issued to the activation input during run mode the device interprets this as a shut down signal and deactivates the current run mode. The shut down feature causes a problem for anyone tying to interface an input to the activation circuit of the auto start module with the output typically associated with a external trigger device that generates a prolonged or latched trigger output. The auto start device will begin the run mode upon reception of a trigger signal to it""s activation input, however, if this signal is maintained at the activation input of the auto start device, the auto start device interprets this as a second trigger signal and terminates the run mode. The transformation of the prolonged or latched output from the trigger device into a momentary output by itself gives the trigger a one shot characteristic whereif the trigger device is still in the trigger state after the run time has expired a new pulse could not be generated to reinitiate the run mode. Furthermore if a trigger is issued to the activation input of the auto start device too soon after the run mode has expired, the signal will not be recognized as a valid activation command and the auto start device will not reinitiate the run mode.
Known prior art for automatic engine starting devices can be seen in U.S. Pat. Nos. 5,054,569; 5,042,439; 5,000,139; 4,928,778; 4,674,454; 4,296,334; 4,006,723.
The present invention incorporates circuitry which allows various triggering devices to be used to activate any of the generic auto start devices widely available. This is advantageous not only to but especially for those companies and individuals engaged in selling and installing engine auto start devices by permitting an easy interface to their preferred auto start device and any number of triggering devices including, temperature sensors, timers, and latched switches.